The present invention generally relates to flight control dynamics of aircraft. More specifically, the present invention relates to flight control dynamics of aircraft which allows a stable coordinated turn without the use of a rudder.
To perform a stable coordinated turn with a fixed wing aircraft, requires the simultaneous use of a horizontal tail, ailerons, and a rudder. The horizontal tail is used for pitch of the aircraft. The ailerons generates increased lift on the outboard wing of the turn and decreased lift on the inboard wing of the turn. The rudder counterbalances adverse yaw generated by positioning of the ailerons. From aerodynamic theory, it is know that having a finite 3-dimensional airfoil such as a wing in a flow will produce 3-dimensional flow about the airfoil. When freestream air flow encounters a wing, a pressure differential forms between both the top and bottom wing surfaces, which produces lift. The difference in pressure about the wing also causes lateral flow under the wing which curls around the wingtips and creates tip vortices. The tip vortices in turn produce downwash. The downwash has the effect of increasing the local angle of attack about the wing, which creates additional drag. This entire process is known for producing induced drag of an aircraft. It is known that when using an aileron on a wing section, the lift coefficient of the wing section is changed due to movement of the aileron. In effect movement of the aileron changes the shape of the airfoil of the wing section and alters the amount of lift produced. With the increase in lift produced by a wing section due to the change in lift coefficient by the aileron, there is a change in drag on that wing section. With the decrease in lift produced by a wing section due to the change in lift coefficient by the aileron, there is also a change in drag on that wing section. In a banked turn, the outboard wing section experiences an increase in lift and the inboard wing section experiences a decrease in lift. With this, the outboard section experiences an increase in drag greater than the drag observed on the inboard wing section. This difference in drag in relation to each wing section creates the effect of adverse yaw on the wing. It is adverse yaw which requires the use of a rudder to counteract the adverse yaw.
It is an object of the present invention to provide to a flight control means to overcome the requirement of a rudder to make a stable coordinated turn with an aircraft.